The lod0 functions would not be declared but could still be referenced by vertex shaders. BUG=angleproject:3471 Change-Id: I635a8465ce68dc22a6f7387b30bf7e93b14dd67d Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1622741 Commit-Queue: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jiajia Qin <jiajia.qin@intel.com>
